### statistical mechanics

(mechanical behavior based upon probability)

**Statistical mechanics** is the mechanical behavior of
a system whose detailed state is unknown, but for which
an overall (non-detailed) state can be derived through
mathematical probability.

Likely, the original physics problem for which statistical mechanics
was developed is the behavior of gases, e.g., **Boyle's law** or the
**ideal gas law**, modeled as the highly probable result of the
interaction of many molecules. Given the large number of molecules
in everyday systems (e.g., the air in a room), the "probable" behavior
is so probable as to be virtually determined.

Statistical mechanics was worked out using **classical mechanics**
but has been adapted to quantum mechanics.

(*physics,mechanics*)
http://en.wikipedia.org/wiki/Statistical_mechanics

**Referenced by:**

entropy (S)

Hamiltonian

partition function (Z)

thermodynamics

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